2 mainmenu "Linux Kernel Configuration for x86"
6 bool "64-bit kernel" if ARCH = "x86"
7 default ARCH = "x86_64"
9 Say yes to build a 64-bit kernel - formerly known as x86_64
10 Say no to build a 32-bit kernel - formerly known as i386
21 select HAVE_AOUT if X86_32
24 select HAVE_UNSTABLE_SCHED_CLOCK
27 select HAVE_IOREMAP_PROT
29 select ARCH_WANT_OPTIONAL_GPIOLIB
30 select ARCH_WANT_FRAME_POINTERS
31 select HAVE_KRETPROBES
32 select HAVE_FTRACE_MCOUNT_RECORD
33 select HAVE_DYNAMIC_FTRACE
34 select HAVE_FUNCTION_TRACER
35 select HAVE_FUNCTION_GRAPH_TRACER
36 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
37 select HAVE_FTRACE_NMI_ENTER if DYNAMIC_FTRACE
38 select HAVE_FTRACE_SYSCALLS
41 select HAVE_ARCH_TRACEHOOK
42 select HAVE_GENERIC_DMA_COHERENT if X86_32
43 select HAVE_EFFICIENT_UNALIGNED_ACCESS
44 select USER_STACKTRACE_SUPPORT
45 select HAVE_DMA_API_DEBUG
46 select HAVE_KERNEL_GZIP
47 select HAVE_KERNEL_BZIP2
48 select HAVE_KERNEL_LZMA
52 default "elf32-i386" if X86_32
53 default "elf64-x86-64" if X86_64
57 default "arch/x86/configs/i386_defconfig" if X86_32
58 default "arch/x86/configs/x86_64_defconfig" if X86_64
63 config GENERIC_CMOS_UPDATE
66 config CLOCKSOURCE_WATCHDOG
69 config GENERIC_CLOCKEVENTS
72 config GENERIC_CLOCKEVENTS_BROADCAST
74 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
76 config LOCKDEP_SUPPORT
79 config STACKTRACE_SUPPORT
82 config HAVE_LATENCYTOP_SUPPORT
85 config FAST_CMPXCHG_LOCAL
98 config GENERIC_ISA_DMA
107 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
109 config GENERIC_BUG_RELATIVE_POINTERS
112 config GENERIC_HWEIGHT
118 config ARCH_MAY_HAVE_PC_FDC
121 config RWSEM_GENERIC_SPINLOCK
124 config RWSEM_XCHGADD_ALGORITHM
127 config ARCH_HAS_CPU_IDLE_WAIT
130 config GENERIC_CALIBRATE_DELAY
133 config GENERIC_TIME_VSYSCALL
137 config ARCH_HAS_CPU_RELAX
140 config ARCH_HAS_DEFAULT_IDLE
143 config ARCH_HAS_CACHE_LINE_SIZE
146 config HAVE_SETUP_PER_CPU_AREA
149 config HAVE_DYNAMIC_PER_CPU_AREA
152 config HAVE_CPUMASK_OF_CPU_MAP
155 config ARCH_HIBERNATION_POSSIBLE
158 config ARCH_SUSPEND_POSSIBLE
165 config ARCH_POPULATES_NODE_MAP
172 config ARCH_SUPPORTS_OPTIMIZED_INLINING
175 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
178 # Use the generic interrupt handling code in kernel/irq/:
179 config GENERIC_HARDIRQS
183 config GENERIC_HARDIRQS_NO__DO_IRQ
186 config GENERIC_IRQ_PROBE
190 config GENERIC_PENDING_IRQ
192 depends on GENERIC_HARDIRQS && SMP
195 config USE_GENERIC_SMP_HELPERS
201 depends on X86_32 && SMP
205 depends on X86_64 && SMP
212 config X86_TRAMPOLINE
214 depends on SMP || (64BIT && ACPI_SLEEP)
217 config X86_32_LAZY_GS
219 depends on X86_32 && !CC_STACKPROTECTOR
223 source "init/Kconfig"
224 source "kernel/Kconfig.freezer"
226 menu "Processor type and features"
228 source "kernel/time/Kconfig"
231 bool "Symmetric multi-processing support"
233 This enables support for systems with more than one CPU. If you have
234 a system with only one CPU, like most personal computers, say N. If
235 you have a system with more than one CPU, say Y.
237 If you say N here, the kernel will run on single and multiprocessor
238 machines, but will use only one CPU of a multiprocessor machine. If
239 you say Y here, the kernel will run on many, but not all,
240 singleprocessor machines. On a singleprocessor machine, the kernel
241 will run faster if you say N here.
243 Note that if you say Y here and choose architecture "586" or
244 "Pentium" under "Processor family", the kernel will not work on 486
245 architectures. Similarly, multiprocessor kernels for the "PPro"
246 architecture may not work on all Pentium based boards.
248 People using multiprocessor machines who say Y here should also say
249 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
250 Management" code will be disabled if you say Y here.
252 See also <file:Documentation/i386/IO-APIC.txt>,
253 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
254 <http://www.tldp.org/docs.html#howto>.
256 If you don't know what to do here, say N.
259 bool "Support x2apic"
260 depends on X86_LOCAL_APIC && X86_64 && INTR_REMAP
262 This enables x2apic support on CPUs that have this feature.
264 This allows 32-bit apic IDs (so it can support very large systems),
265 and accesses the local apic via MSRs not via mmio.
267 If you don't know what to do here, say N.
270 bool "Support sparse irq numbering"
271 depends on PCI_MSI || HT_IRQ
273 This enables support for sparse irqs. This is useful for distro
274 kernels that want to define a high CONFIG_NR_CPUS value but still
275 want to have low kernel memory footprint on smaller machines.
277 ( Sparse IRQs can also be beneficial on NUMA boxes, as they spread
278 out the irq_desc[] array in a more NUMA-friendly way. )
280 If you don't know what to do here, say N.
284 depends on SPARSE_IRQ && NUMA
287 bool "Enable MPS table" if ACPI
289 depends on X86_LOCAL_APIC
291 For old smp systems that do not have proper acpi support. Newer systems
292 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
295 bool "Support for big SMP systems with more than 8 CPUs"
296 depends on X86_32 && SMP
298 This option is needed for the systems that have more than 8 CPUs
301 config X86_EXTENDED_PLATFORM
302 bool "Support for extended (non-PC) x86 platforms"
305 If you disable this option then the kernel will only support
306 standard PC platforms. (which covers the vast majority of
309 If you enable this option then you'll be able to select support
310 for the following (non-PC) 32 bit x86 platforms:
314 SGI 320/540 (Visual Workstation)
315 Summit/EXA (IBM x440)
316 Unisys ES7000 IA32 series
318 If you have one of these systems, or if you want to build a
319 generic distribution kernel, say Y here - otherwise say N.
323 config X86_EXTENDED_PLATFORM
324 bool "Support for extended (non-PC) x86 platforms"
327 If you disable this option then the kernel will only support
328 standard PC platforms. (which covers the vast majority of
331 If you enable this option then you'll be able to select support
332 for the following (non-PC) 64 bit x86 platforms:
336 If you have one of these systems, or if you want to build a
337 generic distribution kernel, say Y here - otherwise say N.
339 # This is an alphabetically sorted list of 64 bit extended platforms
340 # Please maintain the alphabetic order if and when there are additions
345 depends on X86_64 && PCI
346 depends on X86_EXTENDED_PLATFORM
348 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
349 supposed to run on these EM64T-based machines. Only choose this option
350 if you have one of these machines.
353 bool "SGI Ultraviolet"
355 depends on X86_EXTENDED_PLATFORM
357 depends on X86_X2APIC
359 This option is needed in order to support SGI Ultraviolet systems.
360 If you don't have one of these, you should say N here.
362 # Following is an alphabetically sorted list of 32 bit extended platforms
363 # Please maintain the alphabetic order if and when there are additions
368 depends on X86_EXTENDED_PLATFORM
370 Select this for an AMD Elan processor.
372 Do not use this option for K6/Athlon/Opteron processors!
374 If unsure, choose "PC-compatible" instead.
377 bool "RDC R-321x SoC"
379 depends on X86_EXTENDED_PLATFORM
381 select X86_REBOOTFIXUPS
383 This option is needed for RDC R-321x system-on-chip, also known
385 If you don't have one of these chips, you should say N here.
387 config X86_32_NON_STANDARD
388 bool "Support non-standard 32-bit SMP architectures"
389 depends on X86_32 && SMP
390 depends on X86_EXTENDED_PLATFORM
392 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
393 subarchitectures. It is intended for a generic binary kernel.
394 if you select them all, kernel will probe it one by one. and will
397 # Alphabetically sorted list of Non standard 32 bit platforms
400 bool "NUMAQ (IBM/Sequent)"
401 depends on X86_32_NON_STANDARD
405 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
406 NUMA multiquad box. This changes the way that processors are
407 bootstrapped, and uses Clustered Logical APIC addressing mode instead
408 of Flat Logical. You will need a new lynxer.elf file to flash your
409 firmware with - send email to <Martin.Bligh@us.ibm.com>.
412 bool "SGI 320/540 (Visual Workstation)"
413 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
414 depends on X86_32_NON_STANDARD
416 The SGI Visual Workstation series is an IA32-based workstation
417 based on SGI systems chips with some legacy PC hardware attached.
419 Say Y here to create a kernel to run on the SGI 320 or 540.
421 A kernel compiled for the Visual Workstation will run on general
422 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
425 bool "Summit/EXA (IBM x440)"
426 depends on X86_32_NON_STANDARD
428 This option is needed for IBM systems that use the Summit/EXA chipset.
429 In particular, it is needed for the x440.
432 bool "Unisys ES7000 IA32 series"
433 depends on X86_32_NON_STANDARD && X86_BIGSMP
435 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
436 supposed to run on an IA32-based Unisys ES7000 system.
438 config SCHED_OMIT_FRAME_POINTER
440 prompt "Single-depth WCHAN output"
443 Calculate simpler /proc/<PID>/wchan values. If this option
444 is disabled then wchan values will recurse back to the
445 caller function. This provides more accurate wchan values,
446 at the expense of slightly more scheduling overhead.
448 If in doubt, say "Y".
450 menuconfig PARAVIRT_GUEST
451 bool "Paravirtualized guest support"
453 Say Y here to get to see options related to running Linux under
454 various hypervisors. This option alone does not add any kernel code.
456 If you say N, all options in this submenu will be skipped and disabled.
460 source "arch/x86/xen/Kconfig"
463 bool "VMI Guest support"
467 VMI provides a paravirtualized interface to the VMware ESX server
468 (it could be used by other hypervisors in theory too, but is not
469 at the moment), by linking the kernel to a GPL-ed ROM module
470 provided by the hypervisor.
473 bool "KVM paravirtualized clock"
475 select PARAVIRT_CLOCK
477 Turning on this option will allow you to run a paravirtualized clock
478 when running over the KVM hypervisor. Instead of relying on a PIT
479 (or probably other) emulation by the underlying device model, the host
480 provides the guest with timing infrastructure such as time of day, and
484 bool "KVM Guest support"
487 This option enables various optimizations for running under the KVM
490 source "arch/x86/lguest/Kconfig"
493 bool "Enable paravirtualization code"
495 This changes the kernel so it can modify itself when it is run
496 under a hypervisor, potentially improving performance significantly
497 over full virtualization. However, when run without a hypervisor
498 the kernel is theoretically slower and slightly larger.
500 config PARAVIRT_SPINLOCKS
501 bool "Paravirtualization layer for spinlocks"
502 depends on PARAVIRT && SMP && EXPERIMENTAL
504 Paravirtualized spinlocks allow a pvops backend to replace the
505 spinlock implementation with something virtualization-friendly
506 (for example, block the virtual CPU rather than spinning).
508 Unfortunately the downside is an up to 5% performance hit on
509 native kernels, with various workloads.
511 If you are unsure how to answer this question, answer N.
513 config PARAVIRT_CLOCK
519 config PARAVIRT_DEBUG
520 bool "paravirt-ops debugging"
521 depends on PARAVIRT && DEBUG_KERNEL
523 Enable to debug paravirt_ops internals. Specifically, BUG if
524 a paravirt_op is missing when it is called.
529 This option adds a kernel parameter 'memtest', which allows memtest
531 memtest=0, mean disabled; -- default
532 memtest=1, mean do 1 test pattern;
534 memtest=4, mean do 4 test patterns.
535 If you are unsure how to answer this question, answer N.
537 config X86_SUMMIT_NUMA
539 depends on X86_32 && NUMA && X86_32_NON_STANDARD
541 config X86_CYCLONE_TIMER
543 depends on X86_32_NON_STANDARD
545 source "arch/x86/Kconfig.cpu"
549 prompt "HPET Timer Support" if X86_32
551 Use the IA-PC HPET (High Precision Event Timer) to manage
552 time in preference to the PIT and RTC, if a HPET is
554 HPET is the next generation timer replacing legacy 8254s.
555 The HPET provides a stable time base on SMP
556 systems, unlike the TSC, but it is more expensive to access,
557 as it is off-chip. You can find the HPET spec at
558 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
560 You can safely choose Y here. However, HPET will only be
561 activated if the platform and the BIOS support this feature.
562 Otherwise the 8254 will be used for timing services.
564 Choose N to continue using the legacy 8254 timer.
566 config HPET_EMULATE_RTC
568 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
570 # Mark as embedded because too many people got it wrong.
571 # The code disables itself when not needed.
574 bool "Enable DMI scanning" if EMBEDDED
576 Enabled scanning of DMI to identify machine quirks. Say Y
577 here unless you have verified that your setup is not
578 affected by entries in the DMI blacklist. Required by PNP
582 bool "GART IOMMU support" if EMBEDDED
586 depends on X86_64 && PCI
588 Support for full DMA access of devices with 32bit memory access only
589 on systems with more than 3GB. This is usually needed for USB,
590 sound, many IDE/SATA chipsets and some other devices.
591 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
592 based hardware IOMMU and a software bounce buffer based IOMMU used
593 on Intel systems and as fallback.
594 The code is only active when needed (enough memory and limited
595 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
599 bool "IBM Calgary IOMMU support"
601 depends on X86_64 && PCI && EXPERIMENTAL
603 Support for hardware IOMMUs in IBM's xSeries x366 and x460
604 systems. Needed to run systems with more than 3GB of memory
605 properly with 32-bit PCI devices that do not support DAC
606 (Double Address Cycle). Calgary also supports bus level
607 isolation, where all DMAs pass through the IOMMU. This
608 prevents them from going anywhere except their intended
609 destination. This catches hard-to-find kernel bugs and
610 mis-behaving drivers and devices that do not use the DMA-API
611 properly to set up their DMA buffers. The IOMMU can be
612 turned off at boot time with the iommu=off parameter.
613 Normally the kernel will make the right choice by itself.
616 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
618 prompt "Should Calgary be enabled by default?"
619 depends on CALGARY_IOMMU
621 Should Calgary be enabled by default? if you choose 'y', Calgary
622 will be used (if it exists). If you choose 'n', Calgary will not be
623 used even if it exists. If you choose 'n' and would like to use
624 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
628 bool "AMD IOMMU support"
631 depends on X86_64 && PCI && ACPI
633 With this option you can enable support for AMD IOMMU hardware in
634 your system. An IOMMU is a hardware component which provides
635 remapping of DMA memory accesses from devices. With an AMD IOMMU you
636 can isolate the the DMA memory of different devices and protect the
637 system from misbehaving device drivers or hardware.
639 You can find out if your system has an AMD IOMMU if you look into
640 your BIOS for an option to enable it or if you have an IVRS ACPI
643 config AMD_IOMMU_STATS
644 bool "Export AMD IOMMU statistics to debugfs"
648 This option enables code in the AMD IOMMU driver to collect various
649 statistics about whats happening in the driver and exports that
650 information to userspace via debugfs.
653 # need this always selected by IOMMU for the VIA workaround
657 Support for software bounce buffers used on x86-64 systems
658 which don't have a hardware IOMMU (e.g. the current generation
659 of Intel's x86-64 CPUs). Using this PCI devices which can only
660 access 32-bits of memory can be used on systems with more than
661 3 GB of memory. If unsure, say Y.
664 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
667 def_bool (AMD_IOMMU || DMAR)
670 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
671 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
672 select CPUMASK_OFFSTACK
675 Configure maximum number of CPUS and NUMA Nodes for this architecture.
679 int "Maximum number of CPUs" if SMP && !MAXSMP
680 range 2 8 if SMP && X86_32 && !X86_BIGSMP
681 range 2 512 if SMP && !MAXSMP
683 default "4096" if MAXSMP
684 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
687 This allows you to specify the maximum number of CPUs which this
688 kernel will support. The maximum supported value is 512 and the
689 minimum value which makes sense is 2.
691 This is purely to save memory - each supported CPU adds
692 approximately eight kilobytes to the kernel image.
695 bool "SMT (Hyperthreading) scheduler support"
698 SMT scheduler support improves the CPU scheduler's decision making
699 when dealing with Intel Pentium 4 chips with HyperThreading at a
700 cost of slightly increased overhead in some places. If unsure say
705 prompt "Multi-core scheduler support"
708 Multi-core scheduler support improves the CPU scheduler's decision
709 making when dealing with multi-core CPU chips at a cost of slightly
710 increased overhead in some places. If unsure say N here.
712 source "kernel/Kconfig.preempt"
715 bool "Local APIC support on uniprocessors"
716 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
718 A local APIC (Advanced Programmable Interrupt Controller) is an
719 integrated interrupt controller in the CPU. If you have a single-CPU
720 system which has a processor with a local APIC, you can say Y here to
721 enable and use it. If you say Y here even though your machine doesn't
722 have a local APIC, then the kernel will still run with no slowdown at
723 all. The local APIC supports CPU-generated self-interrupts (timer,
724 performance counters), and the NMI watchdog which detects hard
728 bool "IO-APIC support on uniprocessors"
729 depends on X86_UP_APIC
731 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
732 SMP-capable replacement for PC-style interrupt controllers. Most
733 SMP systems and many recent uniprocessor systems have one.
735 If you have a single-CPU system with an IO-APIC, you can say Y here
736 to use it. If you say Y here even though your machine doesn't have
737 an IO-APIC, then the kernel will still run with no slowdown at all.
739 config X86_LOCAL_APIC
741 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
742 select HAVE_PERF_COUNTERS if (!M386 && !M486)
746 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
748 config X86_VISWS_APIC
750 depends on X86_32 && X86_VISWS
752 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
753 bool "Reroute for broken boot IRQs"
755 depends on X86_IO_APIC
757 This option enables a workaround that fixes a source of
758 spurious interrupts. This is recommended when threaded
759 interrupt handling is used on systems where the generation of
760 superfluous "boot interrupts" cannot be disabled.
762 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
763 entry in the chipset's IO-APIC is masked (as, e.g. the RT
764 kernel does during interrupt handling). On chipsets where this
765 boot IRQ generation cannot be disabled, this workaround keeps
766 the original IRQ line masked so that only the equivalent "boot
767 IRQ" is delivered to the CPUs. The workaround also tells the
768 kernel to set up the IRQ handler on the boot IRQ line. In this
769 way only one interrupt is delivered to the kernel. Otherwise
770 the spurious second interrupt may cause the kernel to bring
771 down (vital) interrupt lines.
773 Only affects "broken" chipsets. Interrupt sharing may be
774 increased on these systems.
777 bool "Machine Check Exception"
779 Machine Check Exception support allows the processor to notify the
780 kernel if it detects a problem (e.g. overheating, component failure).
781 The action the kernel takes depends on the severity of the problem,
782 ranging from a warning message on the console, to halting the machine.
783 Your processor must be a Pentium or newer to support this - check the
784 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
785 have a design flaw which leads to false MCE events - hence MCE is
786 disabled on all P5 processors, unless explicitly enabled with "mce"
787 as a boot argument. Similarly, if MCE is built in and creates a
788 problem on some new non-standard machine, you can boot with "nomce"
789 to disable it. MCE support simply ignores non-MCE processors like
790 the 386 and 486, so nearly everyone can say Y here.
793 depends on X86_32 && X86_MCE
794 bool "Use legacy machine check code (will go away)"
796 select X86_ANCIENT_MCE
798 Use the old i386 machine check code. This is merely intended for
799 testing in a transition period. Try this if you run into any machine
800 check related software problems, but report the problem to
801 linux-kernel. When in doubt say no.
806 default y if (!X86_OLD_MCE && X86_32) || X86_64
810 prompt "Intel MCE features"
811 depends on X86_NEW_MCE && X86_LOCAL_APIC
813 Additional support for intel specific MCE features such as
818 prompt "AMD MCE features"
819 depends on X86_NEW_MCE && X86_LOCAL_APIC
821 Additional support for AMD specific MCE features such as
822 the DRAM Error Threshold.
824 config X86_ANCIENT_MCE
827 prompt "Support for old Pentium 5 / WinChip machine checks"
829 Include support for machine check handling on old Pentium 5 or WinChip
830 systems. These typically need to be enabled explicitely on the command
833 config X86_MCE_THRESHOLD
834 depends on X86_MCE_AMD || X86_MCE_INTEL
838 config X86_MCE_INJECT
839 depends on X86_NEW_MCE
840 tristate "Machine check injector support"
842 Provide support for injecting machine checks for testing purposes.
843 If you don't know what a machine check is and you don't do kernel
844 QA it is safe to say n.
846 config X86_MCE_NONFATAL
847 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
848 depends on X86_OLD_MCE
850 Enabling this feature starts a timer that triggers every 5 seconds which
851 will look at the machine check registers to see if anything happened.
852 Non-fatal problems automatically get corrected (but still logged).
853 Disable this if you don't want to see these messages.
854 Seeing the messages this option prints out may be indicative of dying
855 or out-of-spec (ie, overclocked) hardware.
856 This option only does something on certain CPUs.
857 (AMD Athlon/Duron and Intel Pentium 4)
859 config X86_MCE_P4THERMAL
860 bool "check for P4 thermal throttling interrupt."
861 depends on X86_OLD_MCE && X86_MCE && (X86_UP_APIC || SMP)
863 Enabling this feature will cause a message to be printed when the P4
864 enters thermal throttling.
866 config X86_THERMAL_VECTOR
868 depends on X86_MCE_P4THERMAL || X86_MCE_INTEL
871 bool "Enable VM86 support" if EMBEDDED
875 This option is required by programs like DOSEMU to run 16-bit legacy
876 code on X86 processors. It also may be needed by software like
877 XFree86 to initialize some video cards via BIOS. Disabling this
878 option saves about 6k.
881 tristate "Toshiba Laptop support"
884 This adds a driver to safely access the System Management Mode of
885 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
886 not work on models with a Phoenix BIOS. The System Management Mode
887 is used to set the BIOS and power saving options on Toshiba portables.
889 For information on utilities to make use of this driver see the
890 Toshiba Linux utilities web site at:
891 <http://www.buzzard.org.uk/toshiba/>.
893 Say Y if you intend to run this kernel on a Toshiba portable.
897 tristate "Dell laptop support"
899 This adds a driver to safely access the System Management Mode
900 of the CPU on the Dell Inspiron 8000. The System Management Mode
901 is used to read cpu temperature and cooling fan status and to
902 control the fans on the I8K portables.
904 This driver has been tested only on the Inspiron 8000 but it may
905 also work with other Dell laptops. You can force loading on other
906 models by passing the parameter `force=1' to the module. Use at
909 For information on utilities to make use of this driver see the
910 I8K Linux utilities web site at:
911 <http://people.debian.org/~dz/i8k/>
913 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
916 config X86_REBOOTFIXUPS
917 bool "Enable X86 board specific fixups for reboot"
920 This enables chipset and/or board specific fixups to be done
921 in order to get reboot to work correctly. This is only needed on
922 some combinations of hardware and BIOS. The symptom, for which
923 this config is intended, is when reboot ends with a stalled/hung
926 Currently, the only fixup is for the Geode machines using
927 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
929 Say Y if you want to enable the fixup. Currently, it's safe to
930 enable this option even if you don't need it.
934 tristate "/dev/cpu/microcode - microcode support"
937 If you say Y here, you will be able to update the microcode on
938 certain Intel and AMD processors. The Intel support is for the
939 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
940 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
941 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
942 You will obviously need the actual microcode binary data itself
943 which is not shipped with the Linux kernel.
945 This option selects the general module only, you need to select
946 at least one vendor specific module as well.
948 To compile this driver as a module, choose M here: the
949 module will be called microcode.
951 config MICROCODE_INTEL
952 bool "Intel microcode patch loading support"
957 This options enables microcode patch loading support for Intel
960 For latest news and information on obtaining all the required
961 Intel ingredients for this driver, check:
962 <http://www.urbanmyth.org/microcode/>.
965 bool "AMD microcode patch loading support"
969 If you select this option, microcode patch loading support for AMD
970 processors will be enabled.
972 config MICROCODE_OLD_INTERFACE
977 tristate "/dev/cpu/*/msr - Model-specific register support"
979 This device gives privileged processes access to the x86
980 Model-Specific Registers (MSRs). It is a character device with
981 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
982 MSR accesses are directed to a specific CPU on multi-processor
986 tristate "/dev/cpu/*/cpuid - CPU information support"
988 This device gives processes access to the x86 CPUID instruction to
989 be executed on a specific processor. It is a character device
990 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
994 tristate "/sys/kernel/debug/x86/cpu/* - CPU Debug support"
996 If you select this option, this will provide various x86 CPUs
997 information through debugfs.
1000 prompt "High Memory Support"
1001 default HIGHMEM4G if !X86_NUMAQ
1002 default HIGHMEM64G if X86_NUMAQ
1007 depends on !X86_NUMAQ
1009 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1010 However, the address space of 32-bit x86 processors is only 4
1011 Gigabytes large. That means that, if you have a large amount of
1012 physical memory, not all of it can be "permanently mapped" by the
1013 kernel. The physical memory that's not permanently mapped is called
1016 If you are compiling a kernel which will never run on a machine with
1017 more than 1 Gigabyte total physical RAM, answer "off" here (default
1018 choice and suitable for most users). This will result in a "3GB/1GB"
1019 split: 3GB are mapped so that each process sees a 3GB virtual memory
1020 space and the remaining part of the 4GB virtual memory space is used
1021 by the kernel to permanently map as much physical memory as
1024 If the machine has between 1 and 4 Gigabytes physical RAM, then
1027 If more than 4 Gigabytes is used then answer "64GB" here. This
1028 selection turns Intel PAE (Physical Address Extension) mode on.
1029 PAE implements 3-level paging on IA32 processors. PAE is fully
1030 supported by Linux, PAE mode is implemented on all recent Intel
1031 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1032 then the kernel will not boot on CPUs that don't support PAE!
1034 The actual amount of total physical memory will either be
1035 auto detected or can be forced by using a kernel command line option
1036 such as "mem=256M". (Try "man bootparam" or see the documentation of
1037 your boot loader (lilo or loadlin) about how to pass options to the
1038 kernel at boot time.)
1040 If unsure, say "off".
1044 depends on !X86_NUMAQ
1046 Select this if you have a 32-bit processor and between 1 and 4
1047 gigabytes of physical RAM.
1051 depends on !M386 && !M486
1054 Select this if you have a 32-bit processor and more than 4
1055 gigabytes of physical RAM.
1060 depends on EXPERIMENTAL
1061 prompt "Memory split" if EMBEDDED
1065 Select the desired split between kernel and user memory.
1067 If the address range available to the kernel is less than the
1068 physical memory installed, the remaining memory will be available
1069 as "high memory". Accessing high memory is a little more costly
1070 than low memory, as it needs to be mapped into the kernel first.
1071 Note that increasing the kernel address space limits the range
1072 available to user programs, making the address space there
1073 tighter. Selecting anything other than the default 3G/1G split
1074 will also likely make your kernel incompatible with binary-only
1077 If you are not absolutely sure what you are doing, leave this
1081 bool "3G/1G user/kernel split"
1082 config VMSPLIT_3G_OPT
1084 bool "3G/1G user/kernel split (for full 1G low memory)"
1086 bool "2G/2G user/kernel split"
1087 config VMSPLIT_2G_OPT
1089 bool "2G/2G user/kernel split (for full 2G low memory)"
1091 bool "1G/3G user/kernel split"
1096 default 0xB0000000 if VMSPLIT_3G_OPT
1097 default 0x80000000 if VMSPLIT_2G
1098 default 0x78000000 if VMSPLIT_2G_OPT
1099 default 0x40000000 if VMSPLIT_1G
1105 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1108 bool "PAE (Physical Address Extension) Support"
1109 depends on X86_32 && !HIGHMEM4G
1111 PAE is required for NX support, and furthermore enables
1112 larger swapspace support for non-overcommit purposes. It
1113 has the cost of more pagetable lookup overhead, and also
1114 consumes more pagetable space per process.
1116 config ARCH_PHYS_ADDR_T_64BIT
1117 def_bool X86_64 || X86_PAE
1119 config DIRECT_GBPAGES
1120 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1124 Allow the kernel linear mapping to use 1GB pages on CPUs that
1125 support it. This can improve the kernel's performance a tiny bit by
1126 reducing TLB pressure. If in doubt, say "Y".
1128 # Common NUMA Features
1130 bool "Numa Memory Allocation and Scheduler Support"
1132 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1133 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1135 Enable NUMA (Non Uniform Memory Access) support.
1137 The kernel will try to allocate memory used by a CPU on the
1138 local memory controller of the CPU and add some more
1139 NUMA awareness to the kernel.
1141 For 64-bit this is recommended if the system is Intel Core i7
1142 (or later), AMD Opteron, or EM64T NUMA.
1144 For 32-bit this is only needed on (rare) 32-bit-only platforms
1145 that support NUMA topologies, such as NUMAQ / Summit, or if you
1146 boot a 32-bit kernel on a 64-bit NUMA platform.
1148 Otherwise, you should say N.
1150 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1151 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1155 prompt "Old style AMD Opteron NUMA detection"
1156 depends on X86_64 && NUMA && PCI
1158 Enable K8 NUMA node topology detection. You should say Y here if
1159 you have a multi processor AMD K8 system. This uses an old
1160 method to read the NUMA configuration directly from the builtin
1161 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1162 instead, which also takes priority if both are compiled in.
1164 config X86_64_ACPI_NUMA
1166 prompt "ACPI NUMA detection"
1167 depends on X86_64 && NUMA && ACPI && PCI
1170 Enable ACPI SRAT based node topology detection.
1172 # Some NUMA nodes have memory ranges that span
1173 # other nodes. Even though a pfn is valid and
1174 # between a node's start and end pfns, it may not
1175 # reside on that node. See memmap_init_zone()
1177 config NODES_SPAN_OTHER_NODES
1179 depends on X86_64_ACPI_NUMA
1182 bool "NUMA emulation"
1183 depends on X86_64 && NUMA
1185 Enable NUMA emulation. A flat machine will be split
1186 into virtual nodes when booted with "numa=fake=N", where N is the
1187 number of nodes. This is only useful for debugging.
1190 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1192 default "9" if MAXSMP
1193 default "6" if X86_64
1194 default "4" if X86_NUMAQ
1196 depends on NEED_MULTIPLE_NODES
1198 Specify the maximum number of NUMA Nodes available on the target
1199 system. Increases memory reserved to accommodate various tables.
1201 config HAVE_ARCH_BOOTMEM
1203 depends on X86_32 && NUMA
1205 config ARCH_HAVE_MEMORY_PRESENT
1207 depends on X86_32 && DISCONTIGMEM
1209 config NEED_NODE_MEMMAP_SIZE
1211 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1213 config HAVE_ARCH_ALLOC_REMAP
1215 depends on X86_32 && NUMA
1217 config ARCH_FLATMEM_ENABLE
1219 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1221 config ARCH_DISCONTIGMEM_ENABLE
1223 depends on NUMA && X86_32
1225 config ARCH_DISCONTIGMEM_DEFAULT
1227 depends on NUMA && X86_32
1229 config ARCH_SPARSEMEM_DEFAULT
1233 config ARCH_SPARSEMEM_ENABLE
1235 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1236 select SPARSEMEM_STATIC if X86_32
1237 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1239 config ARCH_SELECT_MEMORY_MODEL
1241 depends on ARCH_SPARSEMEM_ENABLE
1243 config ARCH_MEMORY_PROBE
1245 depends on MEMORY_HOTPLUG
1250 bool "Allocate 3rd-level pagetables from highmem"
1251 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1253 The VM uses one page table entry for each page of physical memory.
1254 For systems with a lot of RAM, this can be wasteful of precious
1255 low memory. Setting this option will put user-space page table
1256 entries in high memory.
1258 config X86_CHECK_BIOS_CORRUPTION
1259 bool "Check for low memory corruption"
1261 Periodically check for memory corruption in low memory, which
1262 is suspected to be caused by BIOS. Even when enabled in the
1263 configuration, it is disabled at runtime. Enable it by
1264 setting "memory_corruption_check=1" on the kernel command
1265 line. By default it scans the low 64k of memory every 60
1266 seconds; see the memory_corruption_check_size and
1267 memory_corruption_check_period parameters in
1268 Documentation/kernel-parameters.txt to adjust this.
1270 When enabled with the default parameters, this option has
1271 almost no overhead, as it reserves a relatively small amount
1272 of memory and scans it infrequently. It both detects corruption
1273 and prevents it from affecting the running system.
1275 It is, however, intended as a diagnostic tool; if repeatable
1276 BIOS-originated corruption always affects the same memory,
1277 you can use memmap= to prevent the kernel from using that
1280 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1281 bool "Set the default setting of memory_corruption_check"
1282 depends on X86_CHECK_BIOS_CORRUPTION
1285 Set whether the default state of memory_corruption_check is
1288 config X86_RESERVE_LOW_64K
1289 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1292 Reserve the first 64K of physical RAM on BIOSes that are known
1293 to potentially corrupt that memory range. A numbers of BIOSes are
1294 known to utilize this area during suspend/resume, so it must not
1295 be used by the kernel.
1297 Set this to N if you are absolutely sure that you trust the BIOS
1298 to get all its memory reservations and usages right.
1300 If you have doubts about the BIOS (e.g. suspend/resume does not
1301 work or there's kernel crashes after certain hardware hotplug
1302 events) and it's not AMI or Phoenix, then you might want to enable
1303 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1304 corruption patterns.
1308 config MATH_EMULATION
1310 prompt "Math emulation" if X86_32
1312 Linux can emulate a math coprocessor (used for floating point
1313 operations) if you don't have one. 486DX and Pentium processors have
1314 a math coprocessor built in, 486SX and 386 do not, unless you added
1315 a 487DX or 387, respectively. (The messages during boot time can
1316 give you some hints here ["man dmesg"].) Everyone needs either a
1317 coprocessor or this emulation.
1319 If you don't have a math coprocessor, you need to say Y here; if you
1320 say Y here even though you have a coprocessor, the coprocessor will
1321 be used nevertheless. (This behavior can be changed with the kernel
1322 command line option "no387", which comes handy if your coprocessor
1323 is broken. Try "man bootparam" or see the documentation of your boot
1324 loader (lilo or loadlin) about how to pass options to the kernel at
1325 boot time.) This means that it is a good idea to say Y here if you
1326 intend to use this kernel on different machines.
1328 More information about the internals of the Linux math coprocessor
1329 emulation can be found in <file:arch/x86/math-emu/README>.
1331 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1332 kernel, it won't hurt.
1335 bool "MTRR (Memory Type Range Register) support"
1337 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1338 the Memory Type Range Registers (MTRRs) may be used to control
1339 processor access to memory ranges. This is most useful if you have
1340 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1341 allows bus write transfers to be combined into a larger transfer
1342 before bursting over the PCI/AGP bus. This can increase performance
1343 of image write operations 2.5 times or more. Saying Y here creates a
1344 /proc/mtrr file which may be used to manipulate your processor's
1345 MTRRs. Typically the X server should use this.
1347 This code has a reasonably generic interface so that similar
1348 control registers on other processors can be easily supported
1351 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1352 Registers (ARRs) which provide a similar functionality to MTRRs. For
1353 these, the ARRs are used to emulate the MTRRs.
1354 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1355 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1356 write-combining. All of these processors are supported by this code
1357 and it makes sense to say Y here if you have one of them.
1359 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1360 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1361 can lead to all sorts of problems, so it's good to say Y here.
1363 You can safely say Y even if your machine doesn't have MTRRs, you'll
1364 just add about 9 KB to your kernel.
1366 See <file:Documentation/x86/mtrr.txt> for more information.
1368 config MTRR_SANITIZER
1370 prompt "MTRR cleanup support"
1373 Convert MTRR layout from continuous to discrete, so X drivers can
1374 add writeback entries.
1376 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1377 The largest mtrr entry size for a continuous block can be set with
1382 config MTRR_SANITIZER_ENABLE_DEFAULT
1383 int "MTRR cleanup enable value (0-1)"
1386 depends on MTRR_SANITIZER
1388 Enable mtrr cleanup default value
1390 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1391 int "MTRR cleanup spare reg num (0-7)"
1394 depends on MTRR_SANITIZER
1396 mtrr cleanup spare entries default, it can be changed via
1397 mtrr_spare_reg_nr=N on the kernel command line.
1401 prompt "x86 PAT support"
1404 Use PAT attributes to setup page level cache control.
1406 PATs are the modern equivalents of MTRRs and are much more
1407 flexible than MTRRs.
1409 Say N here if you see bootup problems (boot crash, boot hang,
1410 spontaneous reboots) or a non-working video driver.
1415 bool "EFI runtime service support"
1418 This enables the kernel to use EFI runtime services that are
1419 available (such as the EFI variable services).
1421 This option is only useful on systems that have EFI firmware.
1422 In addition, you should use the latest ELILO loader available
1423 at <http://elilo.sourceforge.net> in order to take advantage
1424 of EFI runtime services. However, even with this option, the
1425 resultant kernel should continue to boot on existing non-EFI
1430 prompt "Enable seccomp to safely compute untrusted bytecode"
1432 This kernel feature is useful for number crunching applications
1433 that may need to compute untrusted bytecode during their
1434 execution. By using pipes or other transports made available to
1435 the process as file descriptors supporting the read/write
1436 syscalls, it's possible to isolate those applications in
1437 their own address space using seccomp. Once seccomp is
1438 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1439 and the task is only allowed to execute a few safe syscalls
1440 defined by each seccomp mode.
1442 If unsure, say Y. Only embedded should say N here.
1444 config CC_STACKPROTECTOR_ALL
1447 config CC_STACKPROTECTOR
1448 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1449 select CC_STACKPROTECTOR_ALL
1451 This option turns on the -fstack-protector GCC feature. This
1452 feature puts, at the beginning of functions, a canary value on
1453 the stack just before the return address, and validates
1454 the value just before actually returning. Stack based buffer
1455 overflows (that need to overwrite this return address) now also
1456 overwrite the canary, which gets detected and the attack is then
1457 neutralized via a kernel panic.
1459 This feature requires gcc version 4.2 or above, or a distribution
1460 gcc with the feature backported. Older versions are automatically
1461 detected and for those versions, this configuration option is
1462 ignored. (and a warning is printed during bootup)
1464 source kernel/Kconfig.hz
1467 bool "kexec system call"
1469 kexec is a system call that implements the ability to shutdown your
1470 current kernel, and to start another kernel. It is like a reboot
1471 but it is independent of the system firmware. And like a reboot
1472 you can start any kernel with it, not just Linux.
1474 The name comes from the similarity to the exec system call.
1476 It is an ongoing process to be certain the hardware in a machine
1477 is properly shutdown, so do not be surprised if this code does not
1478 initially work for you. It may help to enable device hotplugging
1479 support. As of this writing the exact hardware interface is
1480 strongly in flux, so no good recommendation can be made.
1483 bool "kernel crash dumps"
1484 depends on X86_64 || (X86_32 && HIGHMEM)
1486 Generate crash dump after being started by kexec.
1487 This should be normally only set in special crash dump kernels
1488 which are loaded in the main kernel with kexec-tools into
1489 a specially reserved region and then later executed after
1490 a crash by kdump/kexec. The crash dump kernel must be compiled
1491 to a memory address not used by the main kernel or BIOS using
1492 PHYSICAL_START, or it must be built as a relocatable image
1493 (CONFIG_RELOCATABLE=y).
1494 For more details see Documentation/kdump/kdump.txt
1497 bool "kexec jump (EXPERIMENTAL)"
1498 depends on EXPERIMENTAL
1499 depends on KEXEC && HIBERNATION
1501 Jump between original kernel and kexeced kernel and invoke
1502 code in physical address mode via KEXEC
1504 config PHYSICAL_START
1505 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1508 This gives the physical address where the kernel is loaded.
1510 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1511 bzImage will decompress itself to above physical address and
1512 run from there. Otherwise, bzImage will run from the address where
1513 it has been loaded by the boot loader and will ignore above physical
1516 In normal kdump cases one does not have to set/change this option
1517 as now bzImage can be compiled as a completely relocatable image
1518 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1519 address. This option is mainly useful for the folks who don't want
1520 to use a bzImage for capturing the crash dump and want to use a
1521 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1522 to be specifically compiled to run from a specific memory area
1523 (normally a reserved region) and this option comes handy.
1525 So if you are using bzImage for capturing the crash dump,
1526 leave the value here unchanged to 0x1000000 and set
1527 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1528 for capturing the crash dump change this value to start of
1529 the reserved region. In other words, it can be set based on
1530 the "X" value as specified in the "crashkernel=YM@XM"
1531 command line boot parameter passed to the panic-ed
1532 kernel. Please take a look at Documentation/kdump/kdump.txt
1533 for more details about crash dumps.
1535 Usage of bzImage for capturing the crash dump is recommended as
1536 one does not have to build two kernels. Same kernel can be used
1537 as production kernel and capture kernel. Above option should have
1538 gone away after relocatable bzImage support is introduced. But it
1539 is present because there are users out there who continue to use
1540 vmlinux for dump capture. This option should go away down the
1543 Don't change this unless you know what you are doing.
1546 bool "Build a relocatable kernel"
1549 This builds a kernel image that retains relocation information
1550 so it can be loaded someplace besides the default 1MB.
1551 The relocations tend to make the kernel binary about 10% larger,
1552 but are discarded at runtime.
1554 One use is for the kexec on panic case where the recovery kernel
1555 must live at a different physical address than the primary
1558 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1559 it has been loaded at and the compile time physical address
1560 (CONFIG_PHYSICAL_START) is ignored.
1562 # Relocation on x86-32 needs some additional build support
1563 config X86_NEED_RELOCS
1565 depends on X86_32 && RELOCATABLE
1567 config PHYSICAL_ALIGN
1569 prompt "Alignment value to which kernel should be aligned" if X86_32
1571 range 0x2000 0x1000000
1573 This value puts the alignment restrictions on physical address
1574 where kernel is loaded and run from. Kernel is compiled for an
1575 address which meets above alignment restriction.
1577 If bootloader loads the kernel at a non-aligned address and
1578 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1579 address aligned to above value and run from there.
1581 If bootloader loads the kernel at a non-aligned address and
1582 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1583 load address and decompress itself to the address it has been
1584 compiled for and run from there. The address for which kernel is
1585 compiled already meets above alignment restrictions. Hence the
1586 end result is that kernel runs from a physical address meeting
1587 above alignment restrictions.
1589 Don't change this unless you know what you are doing.
1592 bool "Support for hot-pluggable CPUs"
1593 depends on SMP && HOTPLUG
1595 Say Y here to allow turning CPUs off and on. CPUs can be
1596 controlled through /sys/devices/system/cpu.
1597 ( Note: power management support will enable this option
1598 automatically on SMP systems. )
1599 Say N if you want to disable CPU hotplug.
1603 prompt "Compat VDSO support"
1604 depends on X86_32 || IA32_EMULATION
1606 Map the 32-bit VDSO to the predictable old-style address too.
1608 Say N here if you are running a sufficiently recent glibc
1609 version (2.3.3 or later), to remove the high-mapped
1610 VDSO mapping and to exclusively use the randomized VDSO.
1615 bool "Built-in kernel command line"
1618 Allow for specifying boot arguments to the kernel at
1619 build time. On some systems (e.g. embedded ones), it is
1620 necessary or convenient to provide some or all of the
1621 kernel boot arguments with the kernel itself (that is,
1622 to not rely on the boot loader to provide them.)
1624 To compile command line arguments into the kernel,
1625 set this option to 'Y', then fill in the
1626 the boot arguments in CONFIG_CMDLINE.
1628 Systems with fully functional boot loaders (i.e. non-embedded)
1629 should leave this option set to 'N'.
1632 string "Built-in kernel command string"
1633 depends on CMDLINE_BOOL
1636 Enter arguments here that should be compiled into the kernel
1637 image and used at boot time. If the boot loader provides a
1638 command line at boot time, it is appended to this string to
1639 form the full kernel command line, when the system boots.
1641 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1642 change this behavior.
1644 In most cases, the command line (whether built-in or provided
1645 by the boot loader) should specify the device for the root
1648 config CMDLINE_OVERRIDE
1649 bool "Built-in command line overrides boot loader arguments"
1651 depends on CMDLINE_BOOL
1653 Set this option to 'Y' to have the kernel ignore the boot loader
1654 command line, and use ONLY the built-in command line.
1656 This is used to work around broken boot loaders. This should
1657 be set to 'N' under normal conditions.
1661 config ARCH_ENABLE_MEMORY_HOTPLUG
1663 depends on X86_64 || (X86_32 && HIGHMEM)
1665 config ARCH_ENABLE_MEMORY_HOTREMOVE
1667 depends on MEMORY_HOTPLUG
1669 config HAVE_ARCH_EARLY_PFN_TO_NID
1673 menu "Power management and ACPI options"
1675 config ARCH_HIBERNATION_HEADER
1677 depends on X86_64 && HIBERNATION
1679 source "kernel/power/Kconfig"
1681 source "drivers/acpi/Kconfig"
1686 depends on APM || APM_MODULE
1689 tristate "APM (Advanced Power Management) BIOS support"
1690 depends on X86_32 && PM_SLEEP
1692 APM is a BIOS specification for saving power using several different
1693 techniques. This is mostly useful for battery powered laptops with
1694 APM compliant BIOSes. If you say Y here, the system time will be
1695 reset after a RESUME operation, the /proc/apm device will provide
1696 battery status information, and user-space programs will receive
1697 notification of APM "events" (e.g. battery status change).
1699 If you select "Y" here, you can disable actual use of the APM
1700 BIOS by passing the "apm=off" option to the kernel at boot time.
1702 Note that the APM support is almost completely disabled for
1703 machines with more than one CPU.
1705 In order to use APM, you will need supporting software. For location
1706 and more information, read <file:Documentation/power/pm.txt> and the
1707 Battery Powered Linux mini-HOWTO, available from
1708 <http://www.tldp.org/docs.html#howto>.
1710 This driver does not spin down disk drives (see the hdparm(8)
1711 manpage ("man 8 hdparm") for that), and it doesn't turn off
1712 VESA-compliant "green" monitors.
1714 This driver does not support the TI 4000M TravelMate and the ACER
1715 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1716 desktop machines also don't have compliant BIOSes, and this driver
1717 may cause those machines to panic during the boot phase.
1719 Generally, if you don't have a battery in your machine, there isn't
1720 much point in using this driver and you should say N. If you get
1721 random kernel OOPSes or reboots that don't seem to be related to
1722 anything, try disabling/enabling this option (or disabling/enabling
1725 Some other things you should try when experiencing seemingly random,
1728 1) make sure that you have enough swap space and that it is
1730 2) pass the "no-hlt" option to the kernel
1731 3) switch on floating point emulation in the kernel and pass
1732 the "no387" option to the kernel
1733 4) pass the "floppy=nodma" option to the kernel
1734 5) pass the "mem=4M" option to the kernel (thereby disabling
1735 all but the first 4 MB of RAM)
1736 6) make sure that the CPU is not over clocked.
1737 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1738 8) disable the cache from your BIOS settings
1739 9) install a fan for the video card or exchange video RAM
1740 10) install a better fan for the CPU
1741 11) exchange RAM chips
1742 12) exchange the motherboard.
1744 To compile this driver as a module, choose M here: the
1745 module will be called apm.
1749 config APM_IGNORE_USER_SUSPEND
1750 bool "Ignore USER SUSPEND"
1752 This option will ignore USER SUSPEND requests. On machines with a
1753 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1754 series notebooks, it is necessary to say Y because of a BIOS bug.
1756 config APM_DO_ENABLE
1757 bool "Enable PM at boot time"
1759 Enable APM features at boot time. From page 36 of the APM BIOS
1760 specification: "When disabled, the APM BIOS does not automatically
1761 power manage devices, enter the Standby State, enter the Suspend
1762 State, or take power saving steps in response to CPU Idle calls."
1763 This driver will make CPU Idle calls when Linux is idle (unless this
1764 feature is turned off -- see "Do CPU IDLE calls", below). This
1765 should always save battery power, but more complicated APM features
1766 will be dependent on your BIOS implementation. You may need to turn
1767 this option off if your computer hangs at boot time when using APM
1768 support, or if it beeps continuously instead of suspending. Turn
1769 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1770 T400CDT. This is off by default since most machines do fine without
1774 bool "Make CPU Idle calls when idle"
1776 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1777 On some machines, this can activate improved power savings, such as
1778 a slowed CPU clock rate, when the machine is idle. These idle calls
1779 are made after the idle loop has run for some length of time (e.g.,
1780 333 mS). On some machines, this will cause a hang at boot time or
1781 whenever the CPU becomes idle. (On machines with more than one CPU,
1782 this option does nothing.)
1784 config APM_DISPLAY_BLANK
1785 bool "Enable console blanking using APM"
1787 Enable console blanking using the APM. Some laptops can use this to
1788 turn off the LCD backlight when the screen blanker of the Linux
1789 virtual console blanks the screen. Note that this is only used by
1790 the virtual console screen blanker, and won't turn off the backlight
1791 when using the X Window system. This also doesn't have anything to
1792 do with your VESA-compliant power-saving monitor. Further, this
1793 option doesn't work for all laptops -- it might not turn off your
1794 backlight at all, or it might print a lot of errors to the console,
1795 especially if you are using gpm.
1797 config APM_ALLOW_INTS
1798 bool "Allow interrupts during APM BIOS calls"
1800 Normally we disable external interrupts while we are making calls to
1801 the APM BIOS as a measure to lessen the effects of a badly behaving
1802 BIOS implementation. The BIOS should reenable interrupts if it
1803 needs to. Unfortunately, some BIOSes do not -- especially those in
1804 many of the newer IBM Thinkpads. If you experience hangs when you
1805 suspend, try setting this to Y. Otherwise, say N.
1809 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1811 source "drivers/cpuidle/Kconfig"
1813 source "drivers/idle/Kconfig"
1818 menu "Bus options (PCI etc.)"
1823 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1825 Find out whether you have a PCI motherboard. PCI is the name of a
1826 bus system, i.e. the way the CPU talks to the other stuff inside
1827 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1828 VESA. If you have PCI, say Y, otherwise N.
1831 prompt "PCI access mode"
1832 depends on X86_32 && PCI
1835 On PCI systems, the BIOS can be used to detect the PCI devices and
1836 determine their configuration. However, some old PCI motherboards
1837 have BIOS bugs and may crash if this is done. Also, some embedded
1838 PCI-based systems don't have any BIOS at all. Linux can also try to
1839 detect the PCI hardware directly without using the BIOS.
1841 With this option, you can specify how Linux should detect the
1842 PCI devices. If you choose "BIOS", the BIOS will be used,
1843 if you choose "Direct", the BIOS won't be used, and if you
1844 choose "MMConfig", then PCI Express MMCONFIG will be used.
1845 If you choose "Any", the kernel will try MMCONFIG, then the
1846 direct access method and falls back to the BIOS if that doesn't
1847 work. If unsure, go with the default, which is "Any".
1852 config PCI_GOMMCONFIG
1869 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1871 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1874 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1878 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1882 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1889 bool "Support mmconfig PCI config space access"
1890 depends on X86_64 && PCI && ACPI
1893 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1894 depends on PCI_MSI && ACPI && EXPERIMENTAL
1896 DMA remapping (DMAR) devices support enables independent address
1897 translations for Direct Memory Access (DMA) from devices.
1898 These DMA remapping devices are reported via ACPI tables
1899 and include PCI device scope covered by these DMA
1902 config DMAR_DEFAULT_ON
1904 prompt "Enable DMA Remapping Devices by default"
1907 Selecting this option will enable a DMAR device at boot time if
1908 one is found. If this option is not selected, DMAR support can
1909 be enabled by passing intel_iommu=on to the kernel. It is
1910 recommended you say N here while the DMAR code remains
1915 prompt "Support for Graphics workaround"
1918 Current Graphics drivers tend to use physical address
1919 for DMA and avoid using DMA APIs. Setting this config
1920 option permits the IOMMU driver to set a unity map for
1921 all the OS-visible memory. Hence the driver can continue
1922 to use physical addresses for DMA.
1924 config DMAR_FLOPPY_WA
1928 Floppy disk drivers are know to bypass DMA API calls
1929 thereby failing to work when IOMMU is enabled. This
1930 workaround will setup a 1:1 mapping for the first
1931 16M to make floppy (an ISA device) work.
1934 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1935 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1937 Supports Interrupt remapping for IO-APIC and MSI devices.
1938 To use x2apic mode in the CPU's which support x2APIC enhancements or
1939 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1941 source "drivers/pci/pcie/Kconfig"
1943 source "drivers/pci/Kconfig"
1945 # x86_64 have no ISA slots, but do have ISA-style DMA.
1954 Find out whether you have ISA slots on your motherboard. ISA is the
1955 name of a bus system, i.e. the way the CPU talks to the other stuff
1956 inside your box. Other bus systems are PCI, EISA, MicroChannel
1957 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1958 newer boards don't support it. If you have ISA, say Y, otherwise N.
1964 The Extended Industry Standard Architecture (EISA) bus was
1965 developed as an open alternative to the IBM MicroChannel bus.
1967 The EISA bus provided some of the features of the IBM MicroChannel
1968 bus while maintaining backward compatibility with cards made for
1969 the older ISA bus. The EISA bus saw limited use between 1988 and
1970 1995 when it was made obsolete by the PCI bus.
1972 Say Y here if you are building a kernel for an EISA-based machine.
1976 source "drivers/eisa/Kconfig"
1981 MicroChannel Architecture is found in some IBM PS/2 machines and
1982 laptops. It is a bus system similar to PCI or ISA. See
1983 <file:Documentation/mca.txt> (and especially the web page given
1984 there) before attempting to build an MCA bus kernel.
1986 source "drivers/mca/Kconfig"
1989 tristate "NatSemi SCx200 support"
1991 This provides basic support for National Semiconductor's
1992 (now AMD's) Geode processors. The driver probes for the
1993 PCI-IDs of several on-chip devices, so its a good dependency
1994 for other scx200_* drivers.
1996 If compiled as a module, the driver is named scx200.
1998 config SCx200HR_TIMER
1999 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2000 depends on SCx200 && GENERIC_TIME
2003 This driver provides a clocksource built upon the on-chip
2004 27MHz high-resolution timer. Its also a workaround for
2005 NSC Geode SC-1100's buggy TSC, which loses time when the
2006 processor goes idle (as is done by the scheduler). The
2007 other workaround is idle=poll boot option.
2009 config GEODE_MFGPT_TIMER
2011 prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
2012 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
2014 This driver provides a clock event source based on the MFGPT
2015 timer(s) in the CS5535 and CS5536 companion chip for the geode.
2016 MFGPTs have a better resolution and max interval than the
2017 generic PIT, and are suitable for use as high-res timers.
2020 bool "One Laptop Per Child support"
2023 Add support for detecting the unique features of the OLPC
2030 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
2032 source "drivers/pcmcia/Kconfig"
2034 source "drivers/pci/hotplug/Kconfig"
2039 menu "Executable file formats / Emulations"
2041 source "fs/Kconfig.binfmt"
2043 config IA32_EMULATION
2044 bool "IA32 Emulation"
2046 select COMPAT_BINFMT_ELF
2048 Include code to run 32-bit programs under a 64-bit kernel. You should
2049 likely turn this on, unless you're 100% sure that you don't have any
2050 32-bit programs left.
2053 tristate "IA32 a.out support"
2054 depends on IA32_EMULATION
2056 Support old a.out binaries in the 32bit emulation.
2060 depends on IA32_EMULATION
2062 config COMPAT_FOR_U64_ALIGNMENT
2066 config SYSVIPC_COMPAT
2068 depends on COMPAT && SYSVIPC
2073 config HAVE_ATOMIC_IOMAP
2077 source "net/Kconfig"
2079 source "drivers/Kconfig"
2081 source "drivers/firmware/Kconfig"
2085 source "arch/x86/Kconfig.debug"
2087 source "security/Kconfig"
2089 source "crypto/Kconfig"
2091 source "arch/x86/kvm/Kconfig"
2093 source "lib/Kconfig"
projects / linux-2.6 / blob